UC2577T-ADJ - Texas Instruments

Simple Step-Up Voltage Regulator

•Requires Few External Components

•NPN Output Switches 3.0A, 65V(max)

•Extended Input Voltage Range: 3.0V to 40V

•Current Mode Operation for Improved

Transient Response, Line Regulation, and

Current Limiting

•Soft Start Function Provides Controlled

Startup

•52kHz Internal Oscillator

•Output Switch Protected by Current Limit,

Undervoltage Lockout and Thermal

Shutdown

•Improved Replacement for LM2577-ADJ

Series

The UC2577-ADJ device provides all the active functions neces-

sary to implement step-up (boost), flyback, and forward converter

swi tching regulat ors. R equirin g only a few co mponents , these sim-

ple regulators efficiently provide up to 60V as a step-up regulator,

and ev en high er volta ges as a fl yback o r forwa rd converter regula-

tor.

The UC2577-ADJ features a wide input voltage range of 3.0V to

40V an d an adjustable output voltage. An on-chip 3.0A NPN switch

is included with undervoltage lockout, thermal protection circuitry,

and current limiting, as well as soft start mode operation to reduce

current during startup. Other features include a 52kHz fixed fre-

quency on-chip oscillator with no external components and current

mode control for better line and load regulation.

A standard series of inductors and capacitors are available from

several manufacturers optimized for use with these regulators and

are listed in this data sheet.

UC2577-ADJ

3/97

FEATURES DESCRIPTION

CONNECTION DIAGRAM

BLOCK DIAGRAM

UDG-94034

•Simple Boost and Flyback Converters

•SEPIC Topology Permits Input Voltage to

be Higher or Lower than Output Voltage

•Transformer Coupled Forward Regulators

•Multiple Output Designs

TYPICAL APPLICATIONS

5-Pin TO-220 (Top View)

Also available in TO-263 Package.

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

System Parameters

Circuit Figure 1

(Note 3)

Output Voltage VIN = 5V to 10V, ILOAD = 100mA to 800mA 11.40 12.0 12.60 V

TJ = 25°C 11.60 12.40 V

Line Regulation VIN = 3.0V to 10V, ILOAD = 300m A 20 100 mV

TJ = 25°C50mV

Load Regulation VIN = 5V, ILOAD = 100mA to 800m A 20 10 0 mV

TJ = 25°C50mV

Efficiency VIN = 5V, ILOAD = 800mA 80 %

Device Parameters

Input Sup pl y Current VFB = 1.5V (Switch Off) 7.5 14 mA

TJ = 25°C10mA

SWITCH = 2.0A, VCOMP = 2.0V (Max Duty Cycle) 45 85 mA

TJ = 25°C70mA

Input Sup pl y UVLO ISWITCH = 100mA 2.70 2.95 V

TJ = 25°C2.85V

Oscillator Frequency Measured at SWITCH Pin, ISWITCH = 100mA 42 52 62 kH z

TJ = 25°C4856kHz

Referenc e Vol ta ge Measured at FB Pin, VIN = 3.0 V to 40 V, V COMP = 1.0V 1.206 1.230 1.254 V

TJ = 25°C 1.214 1.246 V

Reference Voltage Line Regulation VIN = 3.0V to 40V 0.5 mV

Error Amp Input Bias Current VCOMP = 1.0V 100 800 nA

TJ = 25°C 300 nA

Error Amp Transcon du ct an ce ICOMP = −30µA to +30µA, VCOMP = 1.0V 1600 3700 5800 µmho

TJ = 25°C 2400 4800 µmho

Error Amp Voltag e Gai n VCOMP = 0.8V to 1.6V, RCOMP = 1.0MW (Note 4) 250 800 V/V

TJ = 25°C 500 V/V

Error Amplifier Out put Swin g Upper Limit VFB = 1.0V 2.0 2.4 V

TJ = 25°C2.2V

Lower Li mi t VFB = 1.5V 0.3 0.5 5 V

TJ = 25°C0.40V

Error Amp Output Current VFB = 1.0V to 1.5V, VCOMP = 1.0V ±90 ±200 ±400 µA

TJ = 25°C±130 ±300 µA

Soft Start Curre nt VFB = 1.0V, VCOMP = 0.5V 1.5 5.0 9.5 µA

TJ = 25°C2.57.5

µA

Maxi mu m D uty Cycle VCOMP = 1.5V, ISWITCH = 100mA 90 95 %

TJ = 25°C93%

Unless othe rwise stated, these specifications apply for TA = −40°C to +125°C, VIN =

5V, VFB = VREF, ISWITCH = 0, and TA =TJ.

ELECTRICAL CHARACTERISTICS

RECOMMENDED OPERATING RANGE

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45V

Output Switch Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65V

Output Switch Current (Note 2) . . . . . . . . . . . . . . . . . . . . . 6.0A

Power Dissipation. . . . . . . . . . . . . . . . . . . . . . Internally Limited

Storage Temperature Range . . . . . . . . . . . . . −65°C to +150°C

Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . . 260°C

Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . 150°C

Minimum ESD Rating (C = 100pF, R = 15kΩ) . . . . . . . . . . . 2kV

ABSOLUTE MAXIMUM RATINGS (Note 1)

UC2577-ADJ

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . 3.0V ≤ VIN ≤ 40V

Output Switch Voltage . . . . . . . . . . . . . . . 0V ≤ VSWITCH ≤ 60V

Output Switch Current . . . . . . . . . . . . . . . . . . . . ISWITCH ≤ 3. 0A

Junction Temperature Range. . . . . . . . . . −40°C ≤ TJ ≤ +125°C

UC2577-ADJ

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

Device Parameters (cont.)

Switch Transconductance 12.5 A/V

Switch Leakage Current VSWITCH = 65V, VFB = 1.5V (Switch Off) 10 600 µA

TJ = 25°C300

µA

Switch Saturation Voltage ISWITCH = 2.0A, VCOMP = 2.0V (Max Duty Cycle) 0.5 0.9 V

= 25°C0.7V

NPN Switch Current Limit VCOMP = 2.0V 3.0 4.3 6.0 A

Thermal Resistance Junction to Ambient 65 °C/W

Junction to Case 2 °C/W

COMP Pin Current VCOMP = 0 25 50 µA

TJ = 25°C40

µA

Unless othe rwise stated, these specifications apply for TA = −40°C to +125°C, VIN =

5V, VFB = VREF, ISWITCH = 0, and TA =TJ.

ELECTRICAL CHARACTERISTICS

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings

indic ate conditio ns duri ng wh ic h th e de vi ce is in te nded to be funct io na l, but devic e pa ram et er specifications may not be

guaranteed under these conditi ons. For guaranteed specifications and test conditions, see th e Elect rical Chara c teri stics.

Note 2: Output current cannot be internally limited when the UC2577 is used as a st ep-up regula tor. To prevent damage to

the switch, its curr ent must be external ly limited to 6.0A. However, output current is in terna lly limited when the UC2577 is

used as a flyback or forward converter regulator .

Note 3. External components such as the diode, inductor, input and output capacitors can affect switching regulator

perf ormance. When the UC2 57 7 is use d as sho wn in the Test Circ ui t, sys te m pe rfo r ma nc e wil l be as sp ec ified by the

system pa ramet ers .

Note 4: A 1.0M

Ω

resistor is c onnected to the compen sation pin (wh ich is the error amplifier’s output) to ensure accuracy in

measuring A

VOL.

In ac tual applications, this pin’s load resistance should be

≥

10M

Ω

, resulting in A

VOL

that is typically twice

the guaranteed minimum limit.

Figure 1. Circuit Used to Specify System Parameters

UDG-94035

L = 41 5-0 93 0 (AIE)

D = any manufacturer COUT = Sprague Type 673D

Electrolyti c 680µF, 20V R1 = 48.7k in series with 511Ω (1%)

R2 = 5.62 k (1% )

The Block Diagram shows a step-up switching regulator

utilizing the UC2577. The regulator produces an output

vol tage hig her than the in put vol tage. Th e UC2577 turns

its switch on and off at a fixed frequency of 52kHz, thus

stor ing ener gy in t he indu ctor (L ). When the NPN switch

is on, the inductor current is charged at a rate of VIN/L.

When the switch is off, the voltage at the SWITCH termi-

nal of the inductor rises above VIN, discharging the

stored current through the output diode (D) into the out-

put capacitor (COUT) at a rate of (VOUT - VIN)/L. The en-

ergy stored in the inductor is thus transferred to the

output.

The out put vol tage i s control led by the amount of ener gy

transferred, which is controlled by modulating the peak

inductor current. This modulation is accomplished by

feedi ng a portion of the o utput voltage to an error ampli-

fier which amplif ies the difference between the feedback

voltage and an internal 1.23V precision reference volt-

age. The output of the error amplifier is then compared to

a voltage pr oportional to the switch current, or the induc-

tor current, during the switch on time. A comparator ter-

minates the switch on time when the two voltages are

equal and thus controls the peak switch current to main-

tain a constant output voltage. Figure 2 shows voltage

and current waveforms for the circuit. Formulas for calcu-

lation are shown in Figure 3.

STEP-UP REGULATOR DESIGN PROCEDURE

Refer to the Block Diagram

Given:

VINmin = Minimum input supply voltage

VOUT = Regulated output voltage

UC2577-ADJ

Step-up (Boost) Regulator

Duty Cycle D VOUT + VF − VIN

VOUT + VF − VSAT ≈ VOUT − VIN

VOUT

Avg. In du ct or

Current IIND(AVG) ILOAD

1 − D

Inductor

Current Ripple ∆IIND VIN − VSAT

L • D

52,000

Peak Indu ctor

Current IIND(PK) ILOAD

1−D + ∆IIND

Peak Switch

Current ISW(PK) ILOAD

1−D + ∆IIND

Switch Voltage

when Off VSW(OFF) VOUT + VF

Diode Reverse

Voltage VRVOUT - VSAT

Avg. Diode

Current ID(AVG) ILOAD

Peak Diode

Current ID(PK) ILOAD

1−D + ∆IIND

Power

Dissipation PD0.25Ω 





ILOAD

1−D





2 D + ILOAD • D • VIN

50 (1−D)

VF = Forward Biased Diode Voltage, ILOAD = Output Load

Figure 2. Step-up Regulator Waveforms

First, determine if the UC2577 can provide these values

of VOUT and ILOADmax when operat ing w ith the m inimum

value of VIN. The uppe r li mits for VOUT and ILOADmax are

given by the following equations.

VOUT ≤ 60V and

VOUT ≤ 10 • VINmin

ILOADmax ≤ 2.1A • VINmin

VOUT

These l imits m ust be gre ater tha n or equa l to the values

specified in this application.

1. Output Voltage Section

Resistors R1 and R2 are used to select the desired out-

put voltage. These resistors form a voltage divider and

present a portion of the output v oltage to the error ampli-

fier whi ch compares it to an internal 1.23V reference. Se-

lect R1 and R2 such that:

R2 = VOUT

1.23V − 1

Figure 3. Step-up Regulator Formulas

APPLICATIONS INFORMATION

2. Inductor Selection (L)

A. Preliminary Calculations

To select the inductor, the calculation of the following

three parameters is necessary:

Dmax, the maximum switch duty cycle (0 ≤ D ≤ 0.9):

Dmax = VOUT + VF − VINmin

VOUT + VF − 0.6V

where typically VF = 0.5V for Schottky diodes and VF =

0.8V for fast recovery diodes.

E • T, the product of volts • time that charges the induc-

tor:

E • T = Dmax • (VINmin − 0.6V)106

52,000Hz (V• µs)

IIND, DC, the average inductor current under full load:

IIND, DC = 1.05 • ILOADmax

1 − Dmax

B. Identify Inductor Value:

1. From Figure 4, identify the induc tor code for the region

indicated by the intersection of E • T and IIND, DC. This

code gives the inductor value in microhenries. The L or H

prefix signifies whether the inductor is rated for a maxi-

mum E • T of 90Vµs (L) or 250Vµs (H).

2. If D < 0.85, go to step C. If D ≥ 0.85, calculate the

minimum inductance needed to ensure the switching

regulator’s stability:

0.3 0.4

0.45

0.35 0.5 0.6 0.7 0.8 0.9 1.0 1.5 2.0 2.5 3.0

100

200

150

L47

L68

L100L150L220L330

H2200

L680

H1500 H1000 H680 H470 H330 H220

H150

L470

E·T (V·µs)

IND, DC

(A)

Figure 4. Inductor Selection Graph

If Lmin is smaller than the inductor values found in step

B1, g o on to step C. Otherwise, the inductor value found

in step B1 is too low; an appropriate inductor code

should be obtained from the graph as follows:

1. Find the lowest value inductor that is greater than

Lmin .

2. Find where E • T intersects this inductor value to

determine if it has an L or H prefix. If E • T intersects

both the L and H regions, select the inductor with an

H prefix.

Inductor Selection

Sel ect an i nductor from the table of Figure 5 which cross

refe renc es the in duc tor c ode s t o th e par t numbers of the

thre e di ffere nt m anuf act urer s. The in du ctors lis ted in this

table have the following characteristics:

AIE

(ferrite, pot-core inductors): Benefits of this type

are low etectromagnetic interference (EMI), small

physical size, and very low power dissipation (core

loss).

Pulse

(powdered iron, toroid core inductors): Bene-

fits are low EMI and ability to withstand E • T and

peak current above rated value better than ferrite

cores.

Renco

(ferrite, bobbin-core inductors): Benefits are

low c ost and best abil ity to withstand E • T and peak

current above rated value. Be aware that these in-

duct or s gener ate more EMI than the other types, and

this may interfere with signals sensitive to noise.

UC2577-ADJ

Note: This chart assumes that the inductor ripple current inductor is approximately 20% to 30% of the average inductor current

(when the regulator is under full load). Greater ripple current causes higher peak switch currents and greater output ripple volt-

age. Lower ripple curr ent is achieved with larger value inductors. The factor of 20% to 30% is chosen as a convenient balance

between th e two extremes.

APPLICATIONS INFORMATION (cont.)

UC2577-ADJ

3. Compensation Network (RC, CC) and Output

Capacitor (COUT) Selection

The compensation network consists of resistor RC and

capacitor CC which form a simple pole-zero network and

stabilize the regulator. The values of RC and CC depend

upon the voltage gain of the regulator, ILOADmax, the in-

ductor L, and output capacitance COUT. A procedure to

calculate and select the values for RC, CC, and COUT

which ensures stability is described below. It should be

noted , however, that this may not result in optimum c om-

pens ation . To g uarante e optimum compens ation a stand-

ard procedure for testing loop stability is recommended,

such as measuring VOUT transient responses to pulsing

ILOAD.

A. Calculate the maximum value for R

RC ≤ 750 • ILOADmax • VOUT2

VINmin2

Select a resistor less than or equal to this value, not to

exceed 3kΩ.

B. Calculate the minimum value for C

OUT

using the fol-

lowing two equations.

COUT ≥ 0.19 • L • RC • ILOADmax

VINmin • VOUT and

COUT ≥ VINmin • RC • (VINmin + (3.74 • 105 • L))

487,800 • VOUT3

The larger of these two val ues is the minimum value that

ensures stability.

C. Calculate the minimum value of C

CC ≥ 58.5 • VOUT2 • COUT

RC2 • VINmin

The compensation capacitor is also used in the soft start

function of the regulator. When the input voltage is ap-

pli ed t o the pa rt, the switch duty cycl e is increased slowly

at a rate defined by the compensation capacitor and the

soft start current, thus eliminating high input currents.

Without the soft start circuitry, the switch duty cycle would

instantl y rise to about 90% and draw large currents from

the i nput s up pl y. For p r op er s o ft s tarti ng, the val ue for CC

should be equal or greater than 0.22µF.

Figure 6 lists several types of aluminum electrolytic ca-

pacitors which could be used for the output filter. Use the

following parameters to select the capacitor.

Working Voltage (WVDC):

Choose a capacitor with a

working voltage at least 20% higher than the regulator

output voltage.

Ripple Current:

This is the maximum RMS value of cur-

rent tha t cha rges t he ca paci tor dur ing each swi tching cy-

cle. For step-up and flyback regulators, the formula for

ripple current is:

IRIPPLErms = ILOADmax

• Dmax

1 − Dmax

Cho ose a capac itor that is rated at least 50% hi gher than

this value at 52kHz.

Equivalent Series Resistance (ESR):

This is the primary

caus e of output rippl e vo ltage , and it als o affects the val-

ues of RC and CC neede d to stabilize the regulator. As a

res ult, the preceding calculations for CC and RC ar e only

valid if the ESR does not exceed the maximum value

specified by the following equations.

ESR ≤ 0.01 • 15V

IRIPPLE(P−P) and ≤ 8.7 • 10−3 • VIN

ILOADmax where

IRIPPLE(P−P) = 1.15 • ILOADmax

1 − Dmax

Select a capacitor with an ESR, at 52kHz, that is less

than or eq ual to the lower val ue calculated. Most electro-

lytic capacitors specify ESR at 120kHz which is 15% to

30% higher than at 52kHz. Also, note that ESR increases

by a factor of 2 when operating at −20°C.

In general, low values of ESR are achieved by using

large value capacitors (C ≥ 470µF), and capacitors with

high WVDC, or by paralleling smaller value capacitors.

Inductor

Code Manufacturer’s Part Number

AIE Pulse Renco

L47 415 - 0932 PE - 53112 RL2442

L68 415 - 0931 PE - 92114 RL2443

L100 415 - 0930 PE - 92108 RL2444

L150 415 - 0953 PE - 53113 RL1954

L220 415 - 0922 PE - 52626 RL1953

L330 415 - 0926 PE - 52627 RL1952

L470 415 - 0927 PE - 53114 RL1951

L680 415 - 0928 PE - 52629 RL1950

H150 415 - 0936 PE - 53115 RL2445

H220 430 - 0636 PE - 53116 RL2446

H330 430 - 0635 PE - 53117 RL2447

H470 430 - 0634 PE - 53118 RL1961

H680 415 - 0935 PE - 53119 RL1960

H1000 415 - 0934 PE - 53120 RL1959

H1500 415 - 0933 PE - 53121 RL1958

H2200 415 - 0945 PE - 53122 RL2448

AIE Magnetics, Div. Vernitron Corp., (813)3 47 -21 81

2801 72 nd Stree t Nort h, St. Pet ers bu rg, FL 33710

Pulse Eng ineerin g, (619)674-8100

12220 W o rld Trade Driv e, San Di eg o, CA 9 21 28

Renco Ele ctro ni cs, In c. , (51 6)5 86 -55 66

60 Jef fry n Blv d. East, Dee r Park, NY 11729

Figu re 5. Table of Standardized Indu cto r s an d

Manufacturer’s Part Numbers

APPLICATIONS INFORMATION (cont.)

UNITRODE CORPORATION

7 CONTINENTAL BLVD. • MERRIMACK, NH 03054

TEL. (6 03) 424-2410 • FAX (603 ) 424-3460

4. Input Capacitor Selection (CIN)

To reduce noise on the supply voltage caused by the

switching action of a step-up regulator (ripple current

nois e), V IN sh ould be b ypass ed to g round . A good qual-

ity 0.1µF capacitor with low ESR should provide suffi-

cient decoupling. If the UC2577 is located far from the

supply source filter capacitors, an additional electrolytic

(47µF, for example) is required.

Nichicon - Types PF, PX, or PZ

927 East StateParkway, Scha umburg, IL 60173

(708)843-7500

United Chemi -CON - Types LX, SXF, or SXJ

9801 West Higgens, Rosemont, IL 60018

(708)696-2000

Figure 6. Aluminum Electrolytic Capacitors Recommended

for Switching Regulators

5. Output Diod e Selection (D)

In the step-up regulator, the switching diode must with-

stan d a reverse voltage and be able to conduct the peak

output curr e nt of th e UC 2577. The refore a su i ta bl e diode

must have a minimum reverse breakdown voltage

greater than the circuit output voltage, and should also

be rated for average and peak current greater than

ILOADmax and IDpk. Because of their low forward voltage

drop (and thus higher regulator efficiencies), Schottky

barri e r di o de s are of te n used in swi tchi ng regulators. Re-

fer to Figure 7 for recommended part numbers and volt-

age ratings of 1A and 3A diodes.

VOUTmax Schottky Fast Recovery

1A 3A 1A 3A

20V 1N5817 1N5820

MBR120P MBR320P

30V 1N5818 1N5821

MBR130P MBR330P

11DQ03 31DQ03

40V 1N5819 1N5822

MBR140P MBR340P

11DQ04 31DQ04

50V MBR150 MBR350 1N4933

11DQ05 31DQ05 MUR105

100V 1N4934 MR851

MUR110 30DL1

10DL1 MR831

MBRxx x and MU R x xx are ma nu fa ctured by Motorola .

1DDxxx, 11Cxx and 31Dxx are manufactured by

International Rectifier

Figure 7. Diode Sele ction Chart

UC2577-ADJ

ORDERING INFORMATION

Unitrode Type Number

UC2577TKC-ADJ 5 Pin TO-220 Plastic Pkg -50 pc Tube

UC2577TDKTTT-ADJ 5 Pin TO-263 Plastic Pkg -50 pc Reel

APPLICATIONS INFORMATION (cont.)

PACKAGING INFORMATION

Orderable Device Status (1) Package

Type Package

Drawing Pins Package

Qty Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)

UC2577T-ADJ ACTIVE TO-220 KC 5 50 Green (RoHS &

no Sb/Br) CU SN N / A for Pkg Type

UC2577T-ADJG3 ACTIVE TO-220 KC 5 50 Green (RoHS &

no Sb/Br) CU SN N / A for Pkg Type

UC2577TD-ADJ OBSOLETE DDPAK/

TO-263 KTT 5 TBD Call TI Call TI

UC2577TDKTTT-ADJ ACTIVE DDPAK/

TO-263 KTT 5 50 Green (RoHS &

no Sb/Br) CU SN Level-2-260C-1 YEAR

UC2577TDKTTT-ADJG3 ACTIVE DDPAK/

TO-263 KTT 5 50 Green (RoHS &

no Sb/Br) CU SN Level-2-260C-1 YEAR

UC2577TDTR-ADJ ACTIVE DDPAK/

TO-263 KTT 5 500 Green (RoHS &

no Sb/Br) CU SN Level-2-260C-1 YEAR

UC2577TDTR-ADJG3 ACTIVE DDPAK/

TO-263 KTT 5 500 Green (RoHS &

no Sb/Br) CU SN Level-2-260C-1 YEAR

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in

a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check

http://www.ti.com/productcontent for the latest availability information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements

for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered

at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and

package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS

compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame

retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder

temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is

provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the

accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take

reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on

incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited

information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI

to Customer on an annual basis.

PACKAGE OPTION ADDENDUM

www.ti.com 24-Dec-2007

Addendum-Page 1

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

UC2577TDKTTT-ADJ DDPAK/

TO-263 KTT 5 50 330.0 24.4 10.6 15.6 4.9 16.0 24.0 Q2

UC2577TDTR-ADJ DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.6 15.6 4.9 16.0 24.0 Q2

PACKAGE MATERIALS INFORMATION

www.ti.com 14-Jul-2012

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

UC2577TDKTTT-ADJ DDPAK/TO-263 KTT 5 50 367.0 367.0 45.0

UC2577TDTR-ADJ DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

PACKAGE MATERIALS INFORMATION

www.ti.com 14-Jul-2012

Pack Materials-Page 2

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